Double wall mug



FIG. 1 is an oblique perspective view of the double wall mug;

FIG. 2 is a front view of the double wall mug, as shown in FIG. 1;

FIG. 3 is a back view of the double wall mug;

FIG. 4 is a right side view of the double wall mug;

FIG. 5 is a left side view of the double wall mug;

FIG. 6 is a top view of the double wall mug; and,

FIG. 7 is a bottom view of the double wall mug.

The ornamental design for a double wall mug, as shown and described.